Do you prefer to work late into the night or pop out of bed early to get stuff done? President Barack Obama, Marcel Proust, and Charles Darwin leveraged their night-owl tendencies for greatness, while President George W. Bush, Tim Cook, and Benjamin Franklin reveled in morning work.

Productivity aside, the authors find that both morning and night people can act unethically if you catch them at the time of day when they’re at their worst. People who are wired to work best at night are more prone to making unethical choices in the morning, while morning people are more likely to commit ethical slips at night.

The research responds to a 2013 study showing that people act more ethically in the morning before the rigors of the day wear them down. Gunia, Barnes, and Sah say that fails to factor in that people can usually be divided into three camps—larks, night owls, and in-betweeners—and that 40 percent of people report increased energy during the day.

People don’t necessarily act more ethically early in the day, they contend. The combination of the time of day with a person’s chronotype—how people are wired to work best—helps determine ethical behavior.

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To reach this conclusion, Gunia, Barnes, and Sah performed two experiments. First they asked 48 U.S. MBA students to complete math problems and report how they did. The researchers then checked their self-reported success rate against how they really did. Students got 50¢ for each problem answered correctly, giving them a cash incentive to lie. Students with higher levels of “eveningness” were more likely than people with high levels of “morningness” to inflate their scores if they did them in the morning.

In a second experiment, 142 people were supposed to report the outcome of a die roll in an online study. Students had an incentive to cheat because each number on the die yielded one ticket for a large raffle of prizes. Morning people randomly assigned to roll the die in the evening were more likely to report a higher die roll, while the same was true for night owls in morning sessions.

The results, the authors write, “cast doubt on the stereotype that evening people are somehow dissolute.”